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Polar Vortex 2019

Unread postPosted: Sun 20 Jan 2019, 16:14:11
by Whitefang
I could not find the split PV thread so I thought the issue interesting enough to post, start a new topic on the PV.

The element of surprise..... ... &FORM=VIRE

Funny E40 fat nigga defining the element of surprise.....hihi :roll: ... cillation/

So now to this winter. Even I was surprised how much uncertainty there existed in the models whether the current stratospheric PV disruption would achieve MMW status and if the PV would split. But once confidence was growing that both would be achieved the next question became would the circulation anomalies in the stratosphere couple with the troposphere. And if you measure stratosphere-troposphere coupling in an AO/NAM framework that remains an outstanding question even today. I might be unique but based on a figure that I tweeted out last week and I show in Figure iii, the stratosphere and troposphere are already clearly coupled. I don’t believe that it is a coincidence that the most impressive cold and snow of last week in Central and Southeastern Europe, New England and Eastern Canada were respectively directly beneath the two daughter vortices in the stratosphere. That cold air in New England did something highly anomalous (at least to me) it bled westward and fed the Central Plains to Mid-Atlantic snowstorm. The US is not Europe and normally the cold air does not feed in from the east. But this is an unusual weather event in the stratosphere, and I think expect more surprises.

The Azoren High teamed up with a giant high west or Ireland, never seen that before but Maybe that blocked the low Northeaster that drifted east insteasd of west as usual. ... 920,48.167

Troughing and/or cold temperatures will bring widespread new snowfall to Northern Europe, Turkey, parts of the Middle East, Northern and Eastern Asia (Figure 4). Across North America, troughing and cold temperatures will bring widespread new snowfall across Canada, the Northwestern US and even New England while milder temperatures will result in snowmelt across parts of Alaska and the Mid-Atlantic (Figure 4).

Currently the stratospheric PV remains split into two pieces or daughter vortices. The major daughter vortex is centered near the Urals and a minor daughter vortex is centered over Hudson Bay with ridging centered on Alaska and into the Beaufort Sea and accompanying warming over the North Pole and extending towards Scandinavia (Figure 12). The daughter vortex over the Urals is predicted to drift west across Siberia and fill with time while the other daughter vortex over Hudson Bay remains nearly stationary and deepens so that it becomes the major daughter vortex.

Recent research has shown that regional anomalies that are most highly correlated with the strength of the stratospheric PV are across the Barents-Kara seas region where low Arctic sea ice favors a weaker winter PV. However it is looking more and more like the the greatest negative anomalies are going to persist in the Barents-Kara Seas this winter and this may be the region most favored for ridging/blocking during the winter months. I expect that the forecasts of lower heights and colder temperatures near Alaska will continue to help sea ice grow in the Chukchi and Bering seas in the near term

Re: Polar Vortex

Unread postPosted: Sun 20 Jan 2019, 18:02:38
by Plantagenet
Winters are getting shorter, but paradoxically winters now have more episodes of intense cold weather

NYTimes: climate/polar-vortex


Re: Polar Vortex

Unread postPosted: Sun 20 Jan 2019, 19:00:20
by dissident
This has been beaten to death in other threads. The rapid warming of the Arctic polar cap relative to lower latitudes has resulted in the collapse of the polar front jet that established itself in fall due to the fact that the polar night quickly established very low temperatures due to extensive sea ice cover. Now we have a vast amount of open sea which is delays the onset of very cold temperatures. This results in an evolution bifurcation of the circumpolar zonal wind. Since it is weaker in early polar winter (fall), it is more easily disrupted by baroclinic eddies since the PV gradient is weaker and less elastic (

The result is that the zonality of the circumpolar jet is weak and it exhibits a lot of meander. This meander results in cold Arctic air masses reaching farther south and at the same time warmer middle-latitude air masses reaching closer to the pole. So the winter circulation and weather state in the Norther Hemisphere is now different than it was even 20 years ago. This impacts the stratosphere since the dynamics of the Middle Atmosphere (above the tropopause and below 80 km) is driven wave-mean-flow interaction and weave dissipation. The waves span from planetary vorticity type (i.e. Rossby) to inertia-gravity waves at much smaller scales. The circulation pattern in the troposphere affects the distribution of quasi-stationary Rossby wave fluxes into the stratosphere. Sudden stratospheric warming events (SSWs) are complex phenomena resulting from a resonant (nonlinear transient wave guide) re-focusing of Rossby wave fluxes into the polar cap as opposed to the normal state of propagation towards the the equator on great circle arcs. The geometric confinement of the wave energy into a smaller area/volume results in rapid dynamical warming.

So dynamical trends in the troposphere are reflected by dynamical trends in the stratosphere. It is interesting that in spite of the exponential decay of density with altitude, the state of the stratosphere influences the troposphere. This is partly related to the dynamics of Rossby wave propagation into the stratosphere. Variations in the circulation structure are similar to variations in the refractive index and the amount of Rossby wave flux into the stratosphere is not constant. There are states when more Rossby wave flux is reflected back into the troposphere, which affects the circulation evolution in the troposphere. Various oscillations like the North Atlantic Oscillation (NAO) can be affected by the state of the stratosphere. The NAO affects the baroclinic eddy "storm tracks" which has a leading order impact on the weather.

Re: Polar Vortex

Unread postPosted: Sun 20 Jan 2019, 20:00:01
by dohboi
Nice summary, dis.

It is my understanding that on top of these dynamics, there has been a GW-triggered increase in SSW events, which themselves tend to push cold polar air down into the lower latitudes.

Re: Polar Vortex

Unread postPosted: Sun 20 Jan 2019, 21:30:43
by dissident
dohboi wrote:Nice summary, dis.

It is my understanding that on top of these dynamics, there has been a GW-triggered increase in SSW events, which themselves tend to push cold polar air down into the lower latitudes.

The GW effect is what I describe. GW has changed the circulation in the troposphere, which has impacted the stratosphere and hence SSWs.

SSWs are associated with a change in the structure of the Brewer Dobson-(BD) circulation. The dynamical heating I referred to was the BD downwelling in the polar cap increasing thanks to the focusing of the Rossby wave fluxes towards the poles. (It is too technical, but the change in the Rossby wave fluxes results in a redistribution of the Eliassen-Palm flux divergence towards the pole and hence the associated shift in the BD circulation.)

In terms of a direct impact on the troposphere, the BD circulation is too weak. It attenuates as 1/rho where rho is the air density. So near the surface it is totally dominated by tropospheric circulation features. It is the indirect change in the Rossby wave fluxes that has a larger impact on the troposphere. The energy in Rossby waves is substantial and any trapping of that energy in the troposphere (e.g. via reflection) has a non-negligible impact on the tropospheric dynamics.

The stratosphere acts somewhat like an early warning system. The cooling trend we have seen associated with greenhouse gas increases should have told policy makers that tropospheric warming trend was indisputable. Changes in SSW frequency or timing are also indicators of real change in the troposphere as opposed to "variability". The stratospheric trends are not variability, they reflect systematic changes.

Avalanche alert

Unread postPosted: Tue 22 Jan 2019, 04:45:54
by Whitefang
Thanks for the link plant, the elucidation diss and the extra data gas, all very welcome.
So basicly we could say the stratosphere follows what is underneath and thus enhance or accelerate the effects of abrupt CC, yet another feedback I suppose, feedback upon feedback, an avalanche......

The most important factor of the Earth Climate system seems to be sea surface temperature, 40 feedbacks tied to that one alone.
With sea ice present all is cool and chilled to near freezing, stable summer/spring/fall average temperatures, sea and skye.
Without ice, just like your coke or whiskey on the rocks, temperature on top of the world will increase abruptly, not boiling instantly but say 5 to 20 degrees celcius warmer within a few years. 2022 first BOE, 2025 for SHTF.
That as a result of all those feedbacks kicking in higher gear almost simultaniously, waves, methane mix, currents, vortex, yet, snow cover, rainstorms, permafrost etc etc

The Vortex is tied to a huge mass of cold air on the pole, now mainly centered around the Arctic ocean, with the loss of sea ice that cold mass will be forced down south until a new more or less stable situation is achieved, under these new conditions I see no future for sea ice, even in the dark of winter. So much more moisture in the arctic atmosphere, waves, a continious row of depressions moving in from the Barentz sea, the Gyre reversed, GIS in a full fledged Heinrich event, Northern Atlantic with a statified cold layer surface.

This is bound to have global instant impacts, I think these cold outbursts and yet patterns are the first signs of irreversible and abrupt change of the Vortex/yet and climate system worldwide.
The arctic is already totally different than the one we had 2 decades ago, without sea ice it will be unregognizable, permanently in another phase, solid to fluid.

Just my vieuw, a bit dark for doom looming over our heads, end of agriculture within a decade or two.
I have been wrong before so no need to worry and there is always the terrible and yet......miracles do happen :-D

Monkey Business

Unread postPosted: Tue 22 Jan 2019, 08:10:03
by Whitefang
:oops: Yes, I read it takes the same amount of energy to heat water up to 80 degrees or so, all that energy is ready after lack of albido to go into temperature increase, wind and currents. It has to go somewhere.

It is a huge system, alike our worldwide economy and that fortunately takes time to unravel, time we can use to be prepared and do the right thing, be excellent 8)

Just broke my big tow, running up a slide at a indoor playground called Monkeytown....monkey business :oops:
That in turn creates time for me to post, be with family and take care of my mom and dad with the Alzheimer disaster, I sometimes wish he had an easy thing like cancer/stroke or heart attack, the easy way to go :cry:

With death in mind it is easier to be sober and detached, there is simply no time to act like an immortal, to delay expressing our true feelings and things that need to be done.

American Met.society

Unread postPosted: Thu 24 Jan 2019, 17:21:49
by Whitefang
A linky from plant, then linked to ... -16-0259.1

The extratropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, confining the coldest temperatures at high latitudes. The jet, referred to as the stratospheric polar vortex, is predominantly zonal and centered around the pole; however, it does exhibit large variability in wind speed and location. Previous studies showed that a weak stratospheric polar vortex can lead to cold-air outbreaks in the midlatitudes, but the exact relationships and mechanisms are unclear. Particularly, it is unclear whether stratospheric variability has contributed to the observed anomalous cooling trends in midlatitude Eurasia. Using hierarchical clustering, we show that over the last 37 years, the frequency of weak vortex states in mid- to late winter (January and February) has increased, which was accompanied by subsequent cold extremes in midlatitude Eurasia. For this region, 60% of the observed cooling in the era of Arctic amplification, that is, since 1990, can be explained by the increased frequency of weak stratospheric polar vortex states, a number that increases to almost 80% when El Niño–Southern Oscillation (ENSO) variability is included as well.

Using cluster analysis, we identified dominant patterns of the stratospheric polar vortex in boreal winter. We showed that the polar vortex weakening over the last four decades was a result of more-persistent weak polar vortex states (cluster 7) and less frequent strong polar vortex events (cluster 1) rather than an overall weakening. This shift in polar vortex states can account for most of the recent winter cooling trends over Eurasian midlatitudes via stratosphere–troposphere coupling. The observed sea level pressure and heat flux precursors are in agreement with proposed physical mechanisms and can explain the weakening of the polar vortex via a dynamical troposphere–stratosphere coupling.
Our analysis shows that the Eurasian cooling trend in the era of Arctic amplification can largely be explained by polar vortex variability. Understanding the two-way link between stratospheric and tropospheric circulation is thus essential for understanding winter teleconnections in the Northern Hemisphere. Any improvements in wintertime seasonal forecasts are likely to depend on our comprehension of competing drivers, including the influence of stratospheric variability

From 2017 but still interesting, update online, 2018 supplement: ... 0259.2.pdf ... 046,49.665

One big high Bermuda, another west of Portugal, a tiny one Spitsbergen, teaming up to spread the cold down, wierd weather.

Two lows on the pole….. 8O


Re: Polar Vortex 2019

Unread postPosted: Mon 28 Jan 2019, 19:36:44
by onlooker
"The Polar Vortex Is About to Bring a 'Brutal' And 'Dangerous' Cold to Parts of The US" ... oss-the-us

update on the PV

Unread postPosted: Tue 29 Jan 2019, 09:48:46
by Whitefang ... cillation/

Trying to understand and predict the weather is continuously humbling – just when you feel that you figured a new phenomenon out or take a certain outcome as a given, Mother Nature throws you a surprise. I can appreciate that the public and the media do not consider it newsworthy when the Arctic and Siberia are cold in winter. But I strongly believe that these two regions are on the frontlines of climate change and temperature swings in these regions have implications for the weather across the Northern Hemisphere.

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 10:23:04
by GHung
It's currently 5 degrees (F) colder here in western NC than in Kodiak, AK. This seems to be happening frequently lately, but I'm not sure how far out of the long term norm this is.

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 10:46:36
by Cog
I see the term global warming has been retired for something a great deal more nebulous like climate change.

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 11:03:10
by Newfie
Cog wrote:I see the term global warming has been retired for something a great deal more nebulous like climate change.

You having trouble understanding that?

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 12:43:56
by Cog
Newfie wrote:
Cog wrote:I see the term global warming has been retired for something a great deal more nebulous like climate change.

You having trouble understanding that?

I understand why the term global warming isn't used anymore. Not scary enough. Now any event, any extreme, can be thrown into the basket of man-made climate change, to prove whatever it is the climate doomers want to prove.

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 13:38:46
by yellowcanoe
Cog wrote:I understand why the term global warming isn't used anymore. Not scary enough.

Nope, the reason for using the term "climate change" instead "global warming" is because the changes we are seeing do not always manifest themselves in the form of higher temperatures. Temperature measurements show that the world is getting warmer but we are also seeing more movement of cold arctic air into regions quite far to the south of the arctic. Which is exactly what a lot of Americans in the central and eastern part of the lower 48 are experiencing right now. In recent years these incursions of cold arctic air have become a regular event and not just in North America. Alaskans OTOH seem to be getting a lot more incursions of warm air from the south thereby resulting in temperatures rarely or never before seen in the winter months.

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 13:46:11
by kublikhan
Also the Bush administration pushed to call it "climate change" because it sounded less alarming than global warming:

The terminology shift has political ties. It is well-known by those that have done the research that President George W. Bush's administration preferred the term "climate change" over "global warming." I was an Earth system scientist at NASA during this administration so I am very familiar with how things were unfolding at the time. A political strategist wrote a memo in 2002 urging Republicans to use the term "climate change" because it was less scary than "global warming."

Whatever it is called, do not fall for the attempt to discredit the science because of name... It is just a name game (and a deflection).
Climate Change Or Global Warming? Three Reasons Not To Be Distracted By The Name Game

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 13:49:11
by onlooker
Yep, Yellowcane is right. The overall warming trend disrupts certain patterns that existed, intensifies certain weather events and so some have used an apt metaphor calling it "Climate Weirding"

Re: Polar Vortex 2019

Unread postPosted: Tue 29 Jan 2019, 13:53:58
by onlooker
From the same article that Kub linked:
"Climate change or global climate change is generally considered a “more scientifically accurate term,” than global warming, as NASA explained in 2008, in part because “Changes to precipitation patterns and sea level are likely to have much greater human impact than the higher temperatures alone.” When you consider all of the impacts scientists have observed in recent decades—including the acidifying ocean, worsening wildfires, and more intense deluges—climate scientists are likely to continue favoring the term climate change."